Method and apparatus for producing bulky yarn



P 19, 1961 H. H. PENLAND 3,000,168

METHOD AND APPARATUS FOR PRODUCING BULKY YARN Filed Aug. 21, 1957 FIG. 2

INVENTOR. HILLIARD H. PENLAND AGENT United States Patent 3,000,168 METHOD AND APPARATUS FOR PRODUCING BULKY YARV Hilliard H. Penland, West Asheville, N.C., assignor to American Enka Corporation, Enka, N.C., a corporation of Delaware Filed Aug. 21, 1957, Ser. No. 679,339 2 Claims. (Cl. 5734) This invention relates to the manufacture of bulky yarn and more particularly a method and apparatus for the manufacture of bulky yarn produced from a freshly spun regenerated cellulose multifilament yarn.

It is known to impart to continuous multifilament yarns some of the qualities of spun yarn. For example, Patent No. 2,874,443, there is described a method of displacing the filaments of a continuous yarn by the action of a strong current of air, as the result of which filament loops project outwardly from the body of the threads. This operation shortens the thread, thus increasing the yarn count and the volume of the yarn. The yarn so produced possesses some of the properties associated with both spun and filament yarns. It was noted that the loops contributed only to a very small degree to the strength of the yarn and that a higher covering power was desired in certain end uses, such as tufted rugs.

Along this line, it was discovered in copending application Serial No. 649,719, filed April 1, 1957, now Patent No. 2,959,909, also having common ownership herewith, that a yarn having even greater bulk with a relatively slight increase in denier could be produced by subjecting a freshly spun, after-treated but undried pretwisted continuous multifilament yarn to the action of a strong current of air. Very surprisingly, it was found that the yarn so produced is substantially free of the aforesaid filament loops and has a high degree of body bulk which is important in many end uses for higher denier yarns. While the above referred to disclosures represent valuable advances in the art, there existed a need for finding a way of producing a yarn having properties comparable to the last mentioned yarn without substantially modifying the equipment normally used in the production of viscose rayon yarn and with a view to decreasing the yarn handling costs.

In View of the fact that freshly spun viscose yarn before it has been aftertreated in the usual production thereof, contains a very high amount of liquid and spinbath salts and is sensitive to thread rupture, one skilled in the art would not think a yarn could be bulked before being aftertreated and finished. However, on the contrary, it has now been discovered that a freshly spun viscose yarn can be bulked in a highly satisfactory manner at this point.

An object of the present invention is to provide a novel method for producing a bulked continuous multifilament viscose yarn having a high degree of bulk.

A further object of the present invention is to provide this bulk at a point early in the production of the viscose yarn.

Another object of the present invention is to provide the aforesaid bulk before the yarn is initially taken up in a package form so that the yarn handling costs are decreased.

Still another object of the present invention is to provide an apparatus for bulking freshly spun continuous multifilament yarn.

Other objects will become apparent hereinafter.

These objects are accomplished in accordance with the present invention by extruding viscose into multifilament yarn, continuously passing said yarn through at least one bath, thereafter continuously directing said yarn through a zone in which the tension on said yarn is relaxed, subjecting said yarn to the action of a strong current of a fluid during the travel of said yarn through said zone. Thereafter the yarn is collected in package form.

The invention may be more completely understood by reference to the annexed drawings, wherein:

FIGURE 1 is a schematic view illustrating one embodiment of the present invention wherein freshly spun yarn is bulked after the spinning thereof but before being collected in a spin pot; and

FIGURE 2 is a schematic view showing the yarn after it has been withdrawn from the spinning trough and illustrating another embodiment of the present invention wherein freshly spun yarn is bulked and thereafter collected on a bobbin.

With reference now to FIGURE 1, the first embodiment of the present invention will be described. Reference numeral 10 represents a conventional spinning trough having at least one treating bath, such as illustrated, an acid setting bath 11 and a hot weakly acidic second bath 12. Viscose is pumped through line 13 and forced through the orifices in spinneret 14. Upon being forced through the spinneret into the bath 11, the viscose is formed into yarn 15 having a plurality of filaments. Yarn 15 is withdrawn from bath 11 by godet 16 around which the yarn is wrapped a few times, said godet 16 in operation being positively rotated at a predetermined speed from a source not shown.

Thereafter, the yarn is directed around roller 17 which is freely rotatable and is mounted in bath 12 below the liquid level. The yarn is withdrawn upwardly from bath 12' and is wrapped several times around godet 18. In operation godet 18 is operated at a higher peripheral speed than godet 16 in order to stretch the yarn therebetween.

Next, the yarn is drawn at an angle into a notch provided in the jet generally indicated at 20. A gas, such as air, is supplied under pressure to inlet pipe 21 from a source not shown that propels the yarn through and out of exit conduit 22. Shortly after leaving conduit 22, the direction of yarn travel is changed'while the yarn is still under the influence of the stream of air. The change in direction of the yarn travel results from the yarn being impinged on and deflected from a baffle plate 23 which also disrupts the flow of air leaving jet 20. Then, the bulked yarn is directed onto third godet 24 that is rotated from a source not shown at a peripheral speed less than godet 18 to provide a zone therebetween in which the yarn is under reduced tension.

Due to the action of the air on the yarn in the jet, the denier of the yarn is slightly increased. This shortens the yarn to an amount which compensates for the difference in the peripheral speeds of godet 18 and godet 24. From godet 24 the yarn is allowed to freely fall through a funnel 25 held in position by support 26. The funnel is vertically reciprocated in a centrifugal spin pot 27 that is rotated by spindle 28. Due to the rotation of the pot and the reciprocating action of the funnel, a uniform cake of bulked yarn having some twist is formed as indicated by numeral 30.

With reference now to FIGURE 2 wherein like parts are identified by like reference numerals, the second embodiment will be described. The basic principle involved and operation of this embodiment is essentially the sam as the first, except as noted herein.

In FIGURE 2, yarn 15 after being stretched in the second bath 12 is wrapped around a unitary two step coaxial godet 31 rotated at a predetermined speed from a source not shown. The yarn is first Wrapped around upper step 32 of godet 31. The yarn leaving step 32 is led into jet 20 to be acted upon therein by a stream of air under pressure as described above. After the yarn is bulked due to the influence of the air, it is then led around freely rotatable roller 33 which guides the yarn as indicated in FIGURE 2. Thereafter; the yarn is wrapped around the lower step 34 of godet 31, step 32 having a larger circumference than step 34. Due to the difierence in the circumference between steps 32 and 34, the yarn therebetween is under reduced tension. However, since theaction of the air will shorten the. length of the yarn as pointed out above, compensation will be made for the difierence in'the peripheral speeds of steps 32 and 34. After leaving step '34, the yarn is taken up at a constant speed on a bobbin 35 in an orderly manner.

The second embodiment is advantageous for use in conventional spinning apparatus having two godets. Other than mounting the jet in a suitable position, the only substantial modification of apparatus needed is substituting a godet having a single diameter for one having a two step arrangement described herein. However, the embodiment using a third godet may provide a more flexible arrangement in that the amount of bulk may be changed more easily. For example, if the air pressure is increased to increase the bulk, the speed of the third godet would only have to be decreased when an increase in denier of the yarn occurs. On the other hand, where the two godet system is employed, a different godet may have to be installed in order to compensate for a variation in denier.

After the yarn is collected as shown above, the yarn is subjected to several aftertreatments normally consisting of washing, desulphurizing, bleaching and drying.

The yarn produced by the present invention is particularly characterized by its voluminous and inelastic body. Although the body diameter is notably increased, only a small increase in total denier occurs. A surprising result of the present invention lies in the fact that the aforesaid increase in voluminosity is not removed by the tension to which the yarn is subjected during collecton and the lke.

The following examples are given to further illustrate the practice of the present invention.

Example I A viscose having a cellulose content of 7.5% and a total alkali content of 5.5% was extruded through a 720 hole spinneret into a setting bath. The spinning speed of the yarn was 55 meters per minute. The composition of the bath was 4.6% H 50 12.0% NaOH and 3.7% ZnSO the temperature of the bath being 65 C. The yarn travel in the second bath was 18 inches. The yarn was thereafter wrapped three and a half times around a first godet having a diameter of. 100 mm. and rotated at 90 rpm. After leaving the first godet the yarn was passed to a second bath containing 2.5% H 50 in aqueous solution maintained at 92 C. It was-propelled through the bath for a distance of 20 inches between the guides wherein the yarn was given a high degree of stretch.

The yarn was withdrawn from the second bath and wrapped three and half times around a second godet. The second godet had a diameter of 200 mm. and was rotated at 87 /2 r.p.m., and the denier of the yarn on the second godet was about 1250.

Thereafter the yarn was directed through the jet as described above to which air under a pressure of 82 pounds per square inch was supplied. The direction of the yarn leaving the jet was changed about 90 degrees after which it was wrapped one and a half turns around a third godet having a diameter of 200 mm. and driven at 70 r.p.m. After leaving the third godet the yarn was taken up on a spool rotated at a constant peripheral speed after which the yarn was aftertreated in the usual way. The denier of the yarn after undergoing the above described bulking operation was 1534.

Example 11 The procedure as described in Example I was ,followed except that the yarn was collected with a left hand twist in a spin pot rotated at 2550 r.p.m.; also, the yarn was collected with a right hand twist in a spin pot rotated at 4500 r.p.m. The yarns had twists of one and two turns per inch, respectively. The denier of the yarn collected atthe lower speed was 1334 as compared to a denier of 1250 for the same yarn which had not been bulked. The denier of the yarn collected at the higher speed was 1323 as compared to a denier of 1250 for the same yarn which had not been bulked.

Yarns from the above examples were tufted into carpet material. The yarn produced gave a much better coverage power than yarns processed in like manner but without being subjected to the action of the air.

It is, ofcourse, understood that various changes may be made in the apparatus and process above described without departing from the spirit of the invention. For example, instead of ordinary air, it may be desired to employ air saturated with water or other suitable liquids in order to inhibit salt formation in the yarn during the bulking operation.

What is claimed is:

1. A method of bulking freshly spun viscose rayon yarn comprising extruding viscose into an acid setting bath to form multifilarnent yarn, withdrawing said yarn from said setting bath, passing said yarn through a second Weakly acidic bath, imparting stretch to said yarn, directing said yarn through a zone of reduced tension, directing said yarn into an air jet during its travel through said zone and subjecting the yarn to the. action of a strong current'of air to impart bulk to said yarn and thereafter twisting and collecting said yarn in a rotating centrifugal spin pot.

2. Apparatus for bulking freshly spun continuous multi-filament viscose rayond yarn comprising means for forming a yarn in an acid coagulating bath, means for Withdrawing the yarn from said bath and stretching the same, means for reducing the tension on the ,yarn, a jet disposed in the yarn path between said stretching means and tension reducing means, and means for passing the yarn through the jet including gas supplied under pressure for inducing bulk in the yarn, means for changing the direction of the yarn, and a rapidly rotating centrifugal spin pot for twisting and collecting the bulked yarn in an orderly manner in the form of a cake.

References Cited inthe file of this patent UNITED STATES PATENTS 1,990,617 Sanders et al. Feb. 12, 1935 2,328,074 Hunter Aug. 31, 1943 2,379,824 Mummery July 3, 1945 2,413,123 Underwood Dec. 24, 1946 2,577,915 Piller et al. Dec. 11, 1951 2,614,289 Cresswell et al. Oct. 21, 1952 2,637,069 McKee May 5, 1953 2,783,609 Breen Mar. 5, 1957 2,807,862 Griset Oct. 1, 1957 2,807,864 Head Oct. 1, 1957 2,852,906 Breen Sept. 23, 1958 2,874,445 Griset Feb. 24, 1959 

1. A METHOD OF BULKING FRESHLY SPUN VISCOSE RAYON YARN COMPRISING EXTRUDING VISCOSE INTO AN ACID SETTING BATH TO FORM MULTIFILAMENT YARN, WITHDRAWING SAID YARN FROM SAID SETTING BATH, PASSING SAID YARN THROUGH A SECOND WEAKLY ACIDIC BATH, IMPARTING STRETCH TO SAID YARN, DIRECTING SAID YARN THROUGH A ZONE OF REDUCED TENSION DIRECTING SAID YARN INTO AN AIR JET DURING ITS TRAVEL THROUGH SAID ZONE AND SUBJECTING THE YARN TO THE ACTION OF A STRONG CURRENT OF AIR TO INPART BULK OT SAID YARN AND THEREAFTER TWISTING AND COLLECTING SAID YARN IN A ROTATING CENTRIFUGAL SPIN POT. 